/Engine/Plugins/Editor/ObjectMixer/ObjectMixer/Source/ObjectMixer/Public/Views/List/Modes/ObjectMixerOutlinerHierarchy.h
Forcibly create a parent item for a given tree item
virtual FSceneOutlinerTreeItemPtr FindOrCreateParentItem ( const [ISceneOutlinerTreeItem](API\Editor\SceneOutliner\ISceneOutlinerTreeItem) & Item, const [TMap](API\Runtime\Core\Containers\TMap)< [FSceneOutlinerTreeItemID](API\Editor\SceneOutliner\FSceneOutlinerTreeItemID), FSceneOutlinerTreeItemPtr > & Items, bool bCreate )